fixed multiple style guide violations

lib/assessor.rb

@@ -4,7 +4,7 @@ class Assessor
   def assess(output)
     test_outcome = @testing_framework_adapter.test_outcome(output)
     test_outcome.merge(score: calculate_score(test_outcome))
-  rescue Exception
+  rescue
     {score: 0}
   end
 
@@ -20,7 +20,6 @@ class Assessor
       fail(Error, 'No testing framework adapter set!')
     end
   end
-end
 
-class Assessor::Error < RuntimeError
+  class Error < RuntimeError; end
 end